Jung's contribution to the understanding of the relevance of psychology to alchemy has become increasingly invalidated by the ahistorical nature of his approach, just as his tendency to ignore the importance of cognitive aesthetics for an improved comprehension of the functions of alchemical images has prevented Jungians from further extending Jung's insight of the importance of alchemy for psychology. This paper explores the history of the development of alchemical illustrations in Western Europe from the 14(th) to the 16(th) century, tracing the emergent processes over time. It is only when we take into consideration the historical dimension and the aesthetics of alchemical imagery that it becomes possible to demonstrate how the increasing use of certain aesthetic techniques such as the disjunction and recombination of separate metaphorical elements of previous illustrations, the use of compressive combinations and the use of framing devices worked to gradually increase the cognitive function and the symbolical power of the images. If alchemy is still relevant to psychotherapy it is exactly because it helps us to understand the importance of cognitive aesthetics in our approach to the images, metaphors and narratives of our patients.